Schottky diodes are commonly used in applications requiring fast switching, for example, in power circuits. Also, while standard silicon diodes have a forward voltage drop of about 0.6 volts, Schottky diodes voltage drop at forward biases of around 1 mA is in the range of 0.15V to 0.45 V, making them useful in voltage clamping applications and preventing transistor saturation. This is due to the Schottky diode's higher current density.
FIG. 1 illustrates an application including a power circuit to provide a current to a load circuit. The power circuit includes a high side and a lower side with metal-oxide-semiconductor field effect transistors (MOSFET) PM1 and PM2, respectively. When the high side is turned off, the lower side needs to quickly provide a current. However, body diodes Bdiode, which are parasitic diodes, have low switching speeds. Therefore, an external Schottky diode is typically added to improve the switching performance.
Conventionally, discrete Schottky diodes, which are individual Schottky diodes each individually packaged, are used as external Schottky diodes. However, using discrete Schottky diodes have drawbacks. First, the added connecting wires cause an increase in parasitic capacitance and parasitic conductance, and thus the switching speed of the Schottky diodes are degraded. Furthermore, the manufacturing cost and complexity are increased.
Accordingly, what is needed in the art is a semiconductor device that may incorporate Schottky diodes to take advantage of the benefits associated with increased switching speed while at the same time overcoming the deficiencies of the prior art.